title: Binding of flavor compounds and whey protein isolate as affected by heat and high pressure treatments.
abstract: The interactions of whey protein isolate (WPI) and flavor compounds (2-nonanone, 1-nonanal, and trans-2-nonenal) were investigated, and the influence of flavor compound structure and heat and high pressure denaturation on the interactions were determined by using headspace solid-phase microextraction (SPME) and gas chromatography (GC). The binding of WPI and the flavor compounds decreased in the order trans-2-nonenal > 1-nonanal > 2-nonanone. The differences in binding can be explained with hydrophobic interactions only in the case of 2-nonanone, whereas the aldehydes, in particular trans-2-nonenal, can also react covalently. Heat and high pressure treatment affected protein-flavor interactions depending on the structure of the flavor compound. Upon both heat and high pressure denaturation, the binding of 2-nonanone to WPI decreased, while the binding of 1-nonanal remained unchanged, and the affinity for trans-2-nonenal increased rapidly. The results suggest that hydrophobic interactions are weakened upon heat or high pressure denaturation, whereas covalent interactions are enhanced.
authors.affiliation: Riddet Centre, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
authors.forename: Janina
authors.initials: J
authors.lastname: Kühn
authors.forename: Thérèse
authors.initials: T
authors.lastname: Considine
authors.forename: Harjinder
authors.initials: H
authors.lastname: Singh
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D005421:Flavoring Agents / Q000737:chemistry / Q000378:metabolism*; D006358:Hot Temperature; D007659:Ketones / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011312:Pressure; D011485:Protein Binding; D052617:Solid Phase Microextraction; D000067816:Whey Proteins
chemical_list: D000447:Aldehydes; D005421:Flavoring Agents; D007659:Ketones; D008894:Milk Proteins; D000067816:Whey Proteins; C013166:2-nonenal; C008664:nonanal; C026636:2-nonanone